This cultivar ‘Mnstamepa’ variety was selected by the inventor as a single plant that was the result of a chance hybrid between an unnamed plant of Caesalpinia mexicana with another unnamed plant of Caesalpinia palmeri. The Caesalpinia mexicana plant and the Caesalpinia palmeri plant are unpatented selections originally from native populations. The Caesalpinia mexicana is the female parent in the cross that yielded the seedling which is the Caesalpinia plant ‘Mnstamepa’, the subject of this plant patent application.